McGrady began his work as a vegetable chef in Buckingham Palace, where he cooked for residence staff. Over the course of a long career in the royal kitchens, he became further acquainted with the princess, and after her separation from Prince Charles, McGrady relocated to her new home in Kensington Palace. Diana had recently overcome an eating disorder, and was counting on the chef to prepare her healthy meals. She told him: "I want you to take care of all the fats, and I'll take care of the carbs at the gym."

To meet the princess' demands, McGrady reinvented rich recipes — including a tomato mousse he'd once made for president Ronald Reagan — into fat-free versions, all the while producing a steady supply of comfort foods for William and Henry. (They liked fried chicken, potato skins, and roasted potatoes.) The princess, meanwhile, enjoyed juice — carrots, celery, parsley, and spinach, in addition to beets (which made her blotchy). She frequently ate fresh salads, fish, and stuffed bell peppers. She never ate red meat unless she was entertaining men, when she would she have a rack of lamb.

"The night she was killed, I had the food all ready," he told USA Today. "I never talk about the food I was going to prepare for her when she died."

Diana was supposed to fly into London's Heathrow Airport for a short visit with her children before they returned to school. "I got up in the morning, switched on the TV and I remember the presenter saying, 'For those of you just joining, Princess Diana has died in a car accident.' I thought it was a stunt or a bad joke, but it was on all the channels: We only had four in those days."

The chef was unable to reach Kensington Palace by phone, so he packed up the food and took off. Upon walking into the secretaries' office, the fax machine started. "It was her last will and testament being faxed through," he said. "Everyone began crying."

Aug. 31 marks the 20th anniversary of Princess Diana's death. After all this time, the things McGrady remembers about her the most are "the fun times, treating the boys, [and] the huge shrills of laughter at Kensington Palace." To see the last meals of 22 famous people, click here.